1. Field of the Invention
The present invention generally relates to a connector and a cable connector for balanced transmission; for example, a connector and a cable connector for balanced transmission that are configured to prevent crosstalk between input signals (reception signals) and output signals (transmission signals) in a balanced transmission path.
2. Description of the Related Art
As for methods of transmitting data, there is a typical data transmitting method using a single electric wire. Another method is a balanced transmission method using a pair of electric wires. With the balanced transmission method, positive (+) signals are transmitted simultaneously with negative (−) signals having the same size (magnitude) but different polarities as the positive signals. The balanced transmission method has an advantage of being less susceptible to noise compared to the typical data transmitting method and is widely used in fields of transmitting signals at high speed.
A cable connector configuration used for the balanced transmission method includes a cable having four pairs of output electric wires and four pairs of input electric wires and a pair of balanced transmission connectors, one connector connected to each end of the cable (See, for example, Japanese Laid-Open Patent Publication No. 2003-59593).
The balanced transmission connector has a signal transmission path corresponding to a pair of output signal contacts and another signal transmission path corresponding to a pair of input signal contacts that are formed in parallel. At an area where a pair of output signal contacts and a pair of input signal contacts are situated adjacent to each other, crosstalk may occur between the pairs of output electric wires and input electric wires soldered to a relay wiring substrate.
For example, in order to prevent the crosstalk, Japanese Laid-Open Patent Publication No. 2006-73269 proposes to form an output signal path and an input signal path, one of each on either a front surface or a rear surface of a relay wiring substrate.
Next, a balanced transmission cable connector according to a related art example is described.
FIG. 1 is a perspective view of a related art example of a balanced transmission cable connector 300 observed from a diagonally upper side of the balanced transmission cable connector 300. FIG. 2 is a perspective view of the balanced transmission cable connector 300 observed from a diagonally lower side of the balanced transmission cable connector 300. FIG. 3 is a side view of the balanced transmission cable connector 300. FIG. 4 is a vertical cross-sectional view illustrating where the balanced transmission cable connector 300 is connected to an end part of a relay wiring substrate 200.
As illustrated in FIGS. 1 through 4, the balanced transmission cable connector 300 includes the relay wiring substrate 200 and electric wire pairs (pairs of electric wires) 141 through 148. More specifically, the balanced transmission cable connector 300 includes a contact assembly 380, the relay wiring substrate 200, a balanced transmission wiring cable 130, and a shield cover 150. The contact assembly 380 includes output signal contacts 360 that are formed in pairs with input signal contacts 340 and are arranged in a vertical direction (Z1-Z2 direction). Further, the contact assembly 380 includes planar ground contacts 350 arranged alternately with the pairs of contacts 360, 340 at a prescribed pitch in a horizontal direction (X1-X2 direction).
The contact assembly 380 includes eight contact pairs (1)-(8) sequentially arranged on the front and back surfaces of a connecting part 320a of a block member 390 in the horizontal direction (X1-X2 direction). The contact pairs (1)-(8) are grouped into output signal contact pairs (1)-(4) and input signal contact pairs (5)-(8).
The relay wiring substrate 200 is illustrated in FIGS. 5-7. Contact pads (output signal contact connecting pads) 211-218, which are arranged on a front surface 200a of the relay wiring substrate 200 toward the Y2 direction, form contact pairs (1)-(8) with contact pads 231-238 arranged on a back surface 200b of the relay wiring substrate 200. On the other hand, contact pads (output signal wire connecting pads) 221-228, which are arranged on the front surface 200a of the relay wiring substrate 200 toward the Y1 direction, form contact pairs (1)-(4) with corresponding adjacent contact pads 221-228. Further, contact pads 241-248, which are arranged on the back surface 200b of the relay wiring substrate 200 toward the Y1 direction, form contact pairs (5)-(8) with corresponding adjacent contact pads 241-248. The four pairs of wire connecting contact pads (1)-(4) formed on the front surface 200a of the relay wiring substrate 200 correspond to the output signal contact pairs (1)-(4) of the connecting part 320a of the block member 390. The four pairs of wire connecting contact pads (5)-(8) formed on the back surface 200b of the relay wiring substrate 200 correspond to the input signal contact pairs (5)-(8) of the connecting part 320a of the block member 390. By providing vias (e.g., 252, 282, 301) to wiring patterns (e.g., 250, 253, 251, 261), the wiring patterns forming pairs on both the front and back surfaces 200a, 200b of the relay wiring substrate 200 can be changed to wiring patterns forming pairs on a single side (i.e. front surface 200a or the back surface 200b) of the relay wiring substrate 200.
The relay wiring substrate 200 is a multilayer substrate having a substantially square shape. FIG. 7 illustrates two ground layers 201, 202 provided as inside layers in the relay wiring substrate 200. FIG. 5 illustrates the output signal contact connecting pads 211-218 arranged on the front surface 200a along a side of the relay wiring substrate 200 toward the Y2 direction and the output signal wire connecting pads 221-228 arranged on the back surface 200b along another side of the relay wiring substrate 200 toward the Y1 direction. FIG. 6 illustrates input signal contact connecting pads 231-238 arranged on the back surface 200b along the side of the relay wiring substrate 200 toward the Y2 direction and the input signal wire connecting pads 241-248 arranged on the back surface 200b along the other side of the relay wiring substrate 200 toward the Y1 direction.
The balanced transmission cable 130 has eight wire pairs 141-148 coaxially provided in which four wire pairs 141-144 are arranged at an upper side (Z1 direction) in the X1-X2 directions and four wire pairs 145-148 are arranged at a lower side (Z2 direction) in the X1-X2 directions. Each of the wire pairs 141-148 has first and second signal wires 133-1, 133-2 arranged in the X1-X2 directions. The first and second signal wires 133-1, 133-2 arranged on the upper side are signal wires for output signals and the first and second signal wires 133-1, 133-2 arranged on the lower side are signal wires for input signals.
[Connection Configuration of Relay Wiring Substrate 200 Corresponding to Each Contact Pair]
The wire connecting pad pairs (1)-(4) are arranged on the front surface of the relay wiring substrate 200 and the wire connecting pad pairs (5)-(8) are arranged on the back surface of the relay wiring substrate 200. The wire connecting pad pairs (1)-(4) are arranged in order from the X2 direction to the X1 direction. The direction in which the wire connecting pad pairs (1)-(4) are arranged is the same as the direction in which the output signal contact pairs (1)-(4) are arranged. The wire connecting pad pairs (5)-(8) are arranged in order from the X1 direction to the X2 direction. The direction in which the wire connecting pad pairs (5)-(8) are arranged is the opposite direction to the direction in which the output signal contact pairs (5)-(8) are arranged and the direction in which the wire connecting pad pairs (1)-(4) are arranged.
The ground patterns 330, 331 are formed on the front and back surfaces 200a, 200b of the relay wiring substrate 200 in a manner surrounding the pads (e.g., 211, 231) and wiring patterns (e.g., 250, 251) on the front and back surfaces 200a, 200b of the relay wiring substrate 200. The ground patterns 330, 331 are also formed on the front and back surfaces 200a, 200b of the relay wiring substrate 200 at the spaces in between adjacently arranged pads (e.g., 211, 212, 231, 232) and at the spaces in between adjacently arranged wiring patterns (250, 253, 251, 261) on the front and back surfaces 200a, 200b of the relay wiring substrate 200.
The wiring patterns (e.g., 250, 253) of the relay wiring substrate 200 are formed in a manner spreading from the Y2 side of the relay wiring substrate 200 to the Y1 side of the relay wiring substrate 200 in a fan-like (sector) manner without intersecting each other on the same surface. The wiring patterns of the relay wiring substrate 200 include first wiring patterns 500 extending either on the front surface 200a or the back surface 200b and second wiring patterns 600 spanning between the front surface 200a and back surface 200b by way of the vias (e.g., 252, 282).
The wire connecting pads 221, 222 correspond to the wire connecting pad pair (1). The wire connecting pads 223, 224 correspond to the wire connecting pad pair (2). The wire connecting pads 225, 226 correspond to the wire connecting pad pair (3). The wire connecting pads 227, 228 correspond to the wire connecting pad pair (4).
The wire connecting pads 241, 242 correspond to the wire connecting pad pair (5). The wire connecting pads 243, 244 correspond to the wire connecting pad pair (6). The wire connecting pads 245, 246 correspond to the wire connecting pad pair (7). The wire connecting pads 247, 248 correspond to the wire connecting pad pair (8).
[Connection Between Contact Connecting Pads and Corresponding Contact Pairs]
With reference to FIGS. 1-4, a Y2 direction end of the relay wiring substrate 200 is engaged to a Y1 side of the contact assembly 380. The relay wiring substrate 200 is fixed to the contact assembly 380 by soldering the contact connecting pads 211-218 formed on the front surface 200a to first lead parts of the output signal contacts 360, soldering the contact connecting pads 231-238 formed on the back surface 200b to second lead parts of the input signal contacts 340, and soldering a part of the ground patterns 280, 281 to a fork part 35b of the ground contact 350.
[Corresponding Relationship Between Wire Connecting Pads and Contact Pairs]
In this engaged state, the wire connecting pads 221, 222 correspond to the output signal contact pair (1), the wire connecting pads 223, 224 correspond to the output signal contact pair (2), the wire connecting pads 225, 226 correspond to the output signal contact pair (3), the wire connecting pads 227, 228 correspond to the output signal contact pair (4), the wire connecting pads 241, 242 correspond to the input signal contact pair (5), the wire connecting pads 243, 244 correspond to the input signal contact pairs (6), the wire connecting pads 245, 246 correspond to the input signal contact pair (7), and the wire connecting pads 247, 248 correspond to the input signal contact pair (8).
[Connection Between Balanced Transmission Cable 130 and Relay Wiring Substrate 200]
As illustrated in FIG. 1, among the electric wire pairs 141-148 provided on the end of the balanced transmission cable 130, four electric wire pairs 141-144 are arranged at the upper side (toward the front surface 200a) in the X1-X2 directions. The electric wire pair 141 has each of its first and second signal wires 133-1, 133-2 soldered to corresponding wire connecting pads 221, 222 with solders 290, 291. The electric wire pair 142 has each of its first and second signal wires 133-1, 133-2 soldered to corresponding wire connecting pads 223, 224 with solders 290, 291. The electric wire pair 143 has each of its first and second signal wires 133-1, 133-2 soldered to corresponding wire connecting pads 225, 226 with solders 290, 291. The electric wire pair 144 has each of its first and second signal wires 133-1, 133-2 soldered to corresponding wire connecting pads 227, 228 with solders 290, 291.
As illustrated in FIG. 2, the remaining four electric wire pairs 145-148 are arranged at the lower side (toward the back surface 200b) in the X1-X2 directions. The electric wire pair 145 has each of its first and second signal wires 133-1, 133-2 soldered to corresponding to wire connecting pads 241, 242 with solders 290, 291. The electric wire pair 146 has each of its first and second signal wires 133-1, 133-2 soldered to corresponding wire connecting pads 243, 244 with solders 290, 291. The electric wire pair 147 has each of its first and second signal wires 133-1, 133-2 soldered to corresponding wire connecting pads 245, 246 with solders 290, 291. The electric wire pair 148 has each of its first and second signal wires 133-1, 133-2 soldered to corresponding wire connecting pads 247, 248 with solders 290, 291.
[Connection Between Contact Pairs and Relay Wiring Substrate 200]
The output signal contact pair (1) of the contact assembly 380 is electrically connected to the electric wire pair 141 by way of the contact connecting pads 211, 231, wiring patterns 250, 251, a via 252, a wiring pattern 253, and wire connecting pads 221, 222.
The output signal contact pair (2) of the contact assembly 380 is electrically connected to the electric wire pair 142 by way of the contact connecting pads 212, 232, wiring patterns 260, 261, a via 262, a wiring pattern 261, and wire connecting pads 223, 224.
The output signal contact pair (3) of the contact assembly 380 is electrically connected to the electric wire pair 143 by way of the contact connecting pads 213, 233, wiring patterns 270, 271, a via 272, a wiring pattern 271, and wire connecting pads 225, 226.
The output signal contact pair (4) of the contact assembly 380 is electrically connected to the electric wire pair 144 by way of the contact connecting pads 214, 234, wiring patterns 280, 281, a via 282, a wiring pattern 283, and wire connecting pads 227, 228.
The output signal contact pair (5) of the contact assembly 380 is electrically connected to the electric wire pair 145 by way of the contact connecting pads 215, 235, wiring patterns 290, 291, a via 291, a wiring pattern 292, and wire connecting pads 241, 242.
The output signal contact pair (6) of the contact assembly 380 is electrically connected to the electric wire pair 146 by way of the contact connecting pads 216, 217, wiring patterns 300, 301, a via 301, a wiring pattern 303, and wire connecting pads 243, 244.
The output signal contact pair (7) of the contact assembly 380 is electrically connected to the electric wire pair 147 by way of the contact connecting pads 217, 237, a wiring pattern 310, a via 311, wiring pattern 312, 313 and wire connecting pads 245, 246.
The output signal contact pair (8) of the contact assembly 380 is electrically connected to the electric wire pair 148 by way of the contact connecting pads 218, 238, a wiring pattern 320, a via 321, wiring patterns 322, 323 and wire connecting pads 247, 248.
In other words, the electric wire pairs 141-144 correspond to the output signal contact pairs (1)-(4), and the electric wire pairs 145-148 correspond to the input signal pairs (5)-(8).
As illustrated in FIG. 7, the relay wiring substrate 200 has the two ground layers 201, 202 provided between the first and second signal wires 133-1, 133-2 of the output signal electric wire pairs 141-144 and the first and second signal wires 133-1, 133-2 of the input signal electric wire pairs 145-148 for shielding the output and input signal electric wire pairs 141-148. Thereby, generation of crosstalk between input signals and output signals can be prevented.
With the above-described balanced transmission connector 300, the vias 252, 262, 282, 291, 301, 311, 321 are configured to connect the wiring patterns of the front surface 200a and the back surface 200b by penetrating the front and back surfaces of the relay wiring substrate 200. Because the balanced transmission connector 300 has no ground layer for shielding the vias 252, 262, 282, 291, 301, 311, 321, crosstalk may be generated between the vias of the output signals and the vias of the input signals.